A number of well-known therapies are currently practiced in which a targeted cellular blood component (e.g., red blood cells, white blood cells, and platelets) is separated from whole blood and stored for later infusion to a patient. The targeted cellular product (e.g., red blood cells or platelets) may be in a suspension that includes plasma and/or some other supernatant. As such, it is sometimes desirable to “wash” the cellular suspension (typically with saline) to remove the plasma/supernatant, as well as any non-target cellular material, prior to reinfusion.
Systems and methods for cell washing are exemplified by US 2013/0341291, US 2013/0092630, and US 2014/0199680, each of which is incorporated herein by reference. Each of these published applications discloses cell washing methods utilizing systems and fluid circuits including a spinning membrane separator. Such systems include peristaltic pumps and pinch valves that act on tubing to direct flow within the fluid circuit.
The fluid circuits in the cited published applications have a relatively large internal volume, and thus require relatively large volumes of wash or flush media to clear processed fluid through the fluid circuit. While such systems and fluid circuits are capable of washing and reducing the volume of the targeted cellular component into final volumes of ranging from approximately 50 mL to 5,000 mL, there are instances in which smaller final volumes (e.g., 10 mL) are desired, such as when processing single-dose quantities of mononuclear cell products. Thus, it would be desirable to provide systems and methods for washing small volumes of cellular suspensions.